package com.easy.common.util;

import java.io.ByteArrayOutputStream;
import java.io.UnsupportedEncodingException;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

public class Base64 {
	private static char[] base64EncodeChars = { 
	    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 
	    'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 
	    'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 
	    'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 
	    'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 
	    'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 
	    'w', 'x', 'y', 'z', '0', '1', '2', '3', 
	    '4', '5', '6', '7', '8', '9', '+', '/' 
	};

	private static byte[] base64DecodeChars = { 
	    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 
	    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 
	    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 
	    52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, 
	    -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 
	    15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, 
	    -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 
	    41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1 
	};

	public static String encode(byte[] data) {
	    StringBuffer sb = new StringBuffer();
	    int len = data.length;
	    int i = 0;
	    while (i < len) {
	      int b1 = data[(i++)] & 0xFF;
	      if (i == len) {
	        sb.append(base64EncodeChars[(b1 >>> 2)]);
	        sb.append(base64EncodeChars[((b1 & 0x3) << 4)]);
	        sb.append("==");
	        break;
	      }
	      int b2 = data[(i++)] & 0xFF;
	      if (i == len) {
	        sb.append(base64EncodeChars[(b1 >>> 2)]);
	        sb.append(base64EncodeChars[((b1 & 0x3) << 4 | (b2 & 0xF0) >>> 4)]);
	        sb.append(base64EncodeChars[((b2 & 0xF) << 2)]);
	        sb.append("=");
	        break;
	      }
	      int b3 = data[(i++)] & 0xFF;
	      sb.append(base64EncodeChars[(b1 >>> 2)]);
	      sb.append(base64EncodeChars[((b1 & 0x3) << 4 | (b2 & 0xF0) >>> 4)]);
	      sb.append(base64EncodeChars[((b2 & 0xF) << 2 | (b3 & 0xC0) >>> 6)]);
	      sb.append(base64EncodeChars[(b3 & 0x3F)]);
	    }
	    return sb.toString();
	}

	public static byte[] decode(String str) {
	    byte[] data = str.getBytes();
	    int len = data.length;
	    ByteArrayOutputStream buf = new ByteArrayOutputStream(len);
	    int i = 0;
	    while (i < len) {
	      int b1;
	      do
	        b1 = base64DecodeChars[data[(i++)]];
	      while ((i < len) && (b1 == -1));
	      if (b1 == -1) {
	        break;
	      }
	      int b2;
	      do
	        b2 = base64DecodeChars[data[(i++)]];
	      while ((i < len) && (b2 == -1));
	      if (b2 == -1) {
	        break;
	      }
	      buf.write(b1 << 2 | (b2 & 0x30) >>> 4);
	      int b3;
	      do
	      {
	        b3 = data[(i++)];
	        if (b3 == 61) {
	          return buf.toByteArray();
	        }
	        b3 = base64DecodeChars[b3]; }
	      while ((i < len) && (b3 == -1));
	      if (b3 == -1) {
	        break;
	      }
	      buf.write((b2 & 0xF) << 4 | (b3 & 0x3C) >>> 2);
	      int b4;
	      do
	      {
	        b4 = data[(i++)];
	        if (b4 == 61) {
	          return buf.toByteArray();
	        }
	        b4 = base64DecodeChars[b4]; }
	      while ((i < len) && (b4 == -1));
	      if (b4 == -1) {
	        break;
	      }
	      buf.write((b3 & 0x3) << 6 | b4);
	    }
	    return buf.toByteArray();
	  }
	// 加密  
    public static String getBase64(String str) {  
        byte[] b = null;  
        String s = null;  
        try {  
            b = str.getBytes("utf-8");  
        } catch (UnsupportedEncodingException e) {  
            e.printStackTrace();  
        }  
        if (b != null) {  
            s = new BASE64Encoder().encode(b);  
        }  
        return s;  
    }  
  
    // 解密  
    public static String getFromBase64(String s) {  
        byte[] b = null;  
        String result = null;  
        if (s != null) {  
            BASE64Decoder decoder = new BASE64Decoder();  
            try {  
                b = decoder.decodeBuffer(s);  
                result = new String(b, "utf-8");  
            } catch (Exception e) {  
                e.printStackTrace();  
            }  
        }  
        return result;  
    }  
	public static void main(String[] args) {
		String str = "rest";
		System.out.println(new BASE64Encoder().encode(str.getBytes()));
	}
}
